This limitation doesn't exist. Safari happily opens up to 4 connections per server. There is however a bug with long-polling connections: If you fire off the X

This limitation doesn't exist. Safari happily opens up to 4 connections per server. There is however a bug with long-polling connections: If you fire off the XHR for the long-polling endpoint (or Server Site Events endpoint for that matter) before window.onload has fired, then Safari will not fire onload (nor load any other external resource) until the long-polling connection closes or returns something. What you are seeing is people not updating their scripts yet to take this bug into account.